c# add validation code to method at runtime code example

Example 1: how to reload app.config file at runtime in c#

public static void RefreshAppSettings()
{
   ConfigurationManager.RefreshSection("appSettings");
}

Example 2: code to set error for du[licate entry in php

mysqli_query('INSERT INTO ...');
if (mysqli_errno() == 1062) {
    print 'no way!';
}